CHAPTER 5 HOSE FABRICATION AND MAINTENANCE

CHAPTER 5 HOSE FABRICATION AND MAINTENANCE Chapter Objective: Upon completion of this chapter, you will have a working knowledge of the fabrication and maintenance of aircraft hydraulic and pneumatic hoses and their associated hardware. You are responsible for maintaining a portion of the hundreds of feet of fluid and air lines and various hardware and seals found in modern-day aircraft. The maintenance of these lines frequently involves fabrication and replacement of hose and hose assemblies. To be able to select the proper type of hose and hose assemblies and their hardware, you will need a basic knowledge of the type, size, and material from which items are to be made. HOSE AND HOSE ASSEMBLIES Learning Objective: Identify the various types of hose, hose assemblies, hardware, tools, and equipment used on naval aircraft. Hose assemblies are used to connect moving parts with stationary parts and in locations subject to severe vibration. Hose assemblies are heavier than aluminum-alloy tubing and deteriorate more rapidly. They are used only when absolutely necessary. Hose assemblies are made up of hose and hose fittings. A hose consists of multiple layers of various materials. An example of the hose most often used in medium-pressure applications is shown in figure 5-1. TYPES OF HOSE There are two basic types of hose used in military aircraft and related equipment. They are synthetic rubber and polytetrafluoroethylene, commonly known as Teflon@ or PTFE. Bulk hose identification will vary with the materials from which the hose is constructed. It is important that you are able to clearly identify the proper hose to be used by recognizing the various hose markings. Figure 5-1.—Medium pressure synthetic rubber hose, MIL-H-8794. 5-1